diff --git a/src/Mono.cs b/src/Mono.cs
index b9796ea..17878b9 100644
--- a/src/Mono.cs
+++ b/src/Mono.cs
@@ -5,6 +5,7 @@ namespace snake;
 
 static class Mono
 {
+    public static double game_time = 0.0;
     public static double step_step = 60.0 / 80; // 80|100|120 bpm
     public static double step_time = 0.0;
     public static double step_t = 0.0;
diff --git a/src/Program.cs b/src/Program.cs
index a6a1f41..12be6b4 100644
--- a/src/Program.cs
+++ b/src/Program.cs
@@ -44,6 +44,7 @@ class Program
             // stepper
             if (Time.Total > 3.0)
             {
+                Mono.game_time += Time.Step;
                 Mono.step_time += Time.Step;
                 Mono.step_t = Maths.min(Mono.step_time, Mono.step_step) / Mono.step_step;
             }